LTE is the 3GPP Long Term Evolution project and is the largest new technology research and development project started by the 3GPP in the recent two years, and this technology which takes the OFDM (Orthogonal Frequency Division Multiplexing) and the FDMA (Frequency Division Multiple Addressing) as the key can be seen as a “quasi-4G” technology. The main advantages of the LTE are high peak rate, small system time delay, and supporting flexible bandwidth configuration. For example: a 20 MHz spectrum bandwidth can provide a peak rate of 100 Mbps in downlink and 50 Mbps in uplink, a one-way transmission delay within the user plane is less than 5 ms, and the flexible configuration of 1.25 MHz to 20 MHz bandwidth can be supported, moreover, the carrier aggregation technology can be used to further improve the capacity of cell. The LTE has a broad application prospect.
The paging transmission mode of professional trunking system of CDMA (Code Division Multiple Access) 2000 is hashing according to the terminal IMSI (International Mobile Subscriber Identification Number) and selecting a specific time slot to send, and when the number of users monitored in the group is relatively large, the paging amount is relatively large, moreover the IMSI needs to be brought by a PDS (PTT Dispatch Server) to the BSC (Base Station Controller), and the BSC needs to use some overheads to store the IMSI. The CDMA2000-based professional trunking system has been widely used in the past few years, and how to achieve a smooth transition from the trunking system to 4G in the case that the CDMA 2000 network and the LTE network coexist in the future is a subject worthy of study.